In the battery industry, every battery charger uses some type of control to determine the length of charge. The first controls were simple mechanical timers operating as an on-off switch. As the use of battery powered equipment increased, more attention was given to the safety factors involved during charging. Electronic controllers were designed that mounted inside the charger to solve some of the problems.
Today, all electronic controllers use the current from the battery (to be charged) as their source of power to activate the controller which energizes a relay that turns on the charger. The current to the controller is supplied through the cables that connect the charger to the battery. Once the controller is activated the DC output from the charger is fed to the battery through the same cables. As a result, the controller will continue to receive power (from the charger output) when the battery is disconnected from the charger. The end result is that the charger remains on even though it has been disconnected from the battery. The disconnected cables from the charger thus remain "hot" until the controller is manually reset. This condition of having "hot" charger cables has damaged many systems and has caused serious injuries.
It is the purpose of this invention to provide a circuit, that when added to electronic controllers, will automatically turn off the charger when the battery is disconnected from the charger.